I wanted to love the Ergo, but I didn't. I think I am just too broad-shouldered or big boobed--it wasn't comfortable for me across the chest in the back carry (my child is way too heavy now for me to manage a front carry).
I used a Baby Trekker for a long time and loved it (again, back carry only). I have read here that the position it holds the child in isn't ideal. I think this is more true for the "facing out" position than for the "facing in" one, where there is a bit more of a seat for the child.
The carrier I use and love is the Patapum. It is much like the Ergo, but slightly less padded, and it fits me better at the chest.
I'm hope this isn't against the rules (mods, let me know--I can edit this part out!
), but I do have my Ergo and my Baby Trekker up for auction on eBay right now.